While the Rakata did invent the hyperdrive and once ruled most of the galaxy, their withdrawal from the galaxy was so complete that no trace of their language or culture was left, we know from Kotor that this was at lleast partially deliberate. This means translators would have no reference to work on.

And while translator device have existed, we know by Luke's time they we not in use. since they used C3-P0 as a translator for virtualy every language. So the question is whether the Kotor translator was a one off or not. And since everybody else is understanding everybody else with ease, irrelevant or technology level, such as

It is probable that the language barriers were just ignored